1. Field of the Invention
The present invention is directed to a rotary disc screen for separating loose material, such as glass and similar refuse from waste material that has a high percentage of burnables, and to the method of its operation.
2. Description of the Prior Art
The art of separating material of differing properties, or of classifying materials by rotary screening apparatus is represented by prior art devices such as disclosed in patents to Bray U.S. Pat. No. 622,035 of Mar. 28, 1899, Erickson U.S. Pat. No. 2,743,813 of May 1, 1956, Dunbar U.S. Pat. No. 2,966,267 of Dec. 27, 1960, Kuntz U.S. Pat. No. 2,974,793 of Mar. 14, 1961, and Conway et al U.S. Pat. No. 3,028,957 of Apr. 10, 1962. These patents may be considered to be the forerunners of more sophisticated apparatus having greater capacity for separating or classifying loose materials.
The more recent prior art includes the Disk Separator U.S. Pat. No. 4,037,723 of Wahl et al of July 26, 1977 for separating finer components of material requiring separation from coarse components. The disks are toothed to facilitate moving large objects. The Apparatus For Separation Of Material Of Heterogeneous Character U.S. Pat. No. 4,266,676 of Ruckstuhl of May 12, 1981 handles municipal refuse which is a mixture of various sizes of material that also vary in weight in which discs are non-circular of the ellipical class. The art also includes U.S. Pat. No. 4,301,930 of Smith of Nov. 24, 1981 for a Disk Screen With Modular Assembly and Method for use in the paper pulp industry for screening wood chips.
None of the foregoing devices have recognized a problem of overcoming non-uniform output, that is to say the output may at times be copious and at other times lean. When a copious output reaches the rotary screen it tends to pile up at the screen inlet which clogs the screen and poor results occur. The foregoing problem has been handled by an attendant being stationed at the rotary screen to regulate the speed of rotation of the screen discs so that a more even distribution of the waste material can be achieved. Manual speed regulation is not a satisfactory answer to the problem of obtaining an efficient result from a rotary disc device for screening waste material.